Mobile phones with digital cameras are broadly available in nearly every worldwide market. According to market statistics and forecasts, by 2018, annual smartphone shipments are expected to grow to 1.87 billion units; over 80% of all mobile phones will be arriving to customers with embedded digital cameras. New shipments will expand the already massive current audience of approximately 4.5 billion mobile phone users and seven billion mobile subscribers; new units will also update mobile phones currently used by the subscribers. Annual sales of phone cameras to mobile phone manufacturers for embedding into smartphones and feature phones are projected at 1.5 billion units.
The volume of photographs taken with phone cameras is also growing rapidly. According to recent survey by Pew Research, photographing with phone cameras is the single most popular activity of smartphone owners utilized by 82% of users. According to recent studies, about 27% of all photos have been taken with smartphones. Images from smartphone cameras are more and more dominating social photo sharing sites.
Hundreds of millions smartphone users are increasingly incorporating smartphone cameras into their information capturing and processing lifestyles at work and at home. Digitizing and capturing paper based information becomes ubiquitous. A recent survey of smartphone usage by millennials has revealed that 68% of survey respondents have been introduced to mobile information capturing via mobile check deposits and 83% think that mobile capture will be part of all mobile transactions within the next five years. Additionally, business oriented users are capturing meeting materials and notes from whiteboards, Moleskine and other paper notebooks and other handwritten media. A 2015 study of corporate whiteboard users has discovered that 84% of survey participants experienced a need to store whiteboard content; accordingly, 72% had taken a photograph of a whiteboard at least once, while 29% had at least 10 images of whiteboards saved on their camera enabled smartphones or tablets. The arrival of unified multi-platform content management systems, such as the Evernote service and software developed by Evernote Corporation of Redwood City, Calif., aimed at capturing, storing, displaying and modifying all types and formats of information across all user devices, has facilitated and stimulated capturing of typed and handwritten text, documents, forms, checks, charts, drawings and other types and formats of real-life content with smartphone cameras, as well as other types of cameras and scanners.
Content captured by users using smartphone and other cameras or scanners is initially stored in a content management system as a raster image. Users can view and share such content, but object based processing—selective text modification or copy-pasting, operations with handwritten doodles or charts, etc.—is not instantly available. In response to this challenge, a variety of content vectorization mechanisms and systems have been developed, including Roberts, Canny and Sobel edge detection methods, Potrace and Vextractor vectorization software, etc. These mechanisms aim at converting image content into line art and other traceable object collections.
Notwithstanding a significant progress in vectorization technologies, existing algorithms suffer from significant discrepancies between an original image and a vector representation of the original image. For example, Bezier curves that are broadly used in vectorization are often applied inconsistently and distort characteristic features of handwritten, typed and hand-drawn shapes, such as sharp angles and high curvature pieces of a trajectory, which especially affects vectorization accuracy and processing capabilities for artistic hand-drawn and printed images.
Accordingly, it is useful to develop efficient and accurate mechanisms for vectorization of content captured on raster images.